Ed Moloney, founder of the Boston College Belfast Project archive and author of A Secret History of the IRA. Photograph: John Stillwell/PA

The award-winning journalist behind the controversial Boston College IRA-Ulster loyalist archive has urged the US government to resist police demands that all of the remaining tapes detailing paramilitary testimonies be sent to Belfast.

The Police Service of Northern Ireland has confirmed it is looking to examine all of the 40-plus tapes containing frank confessions from ex-IRA and loyalist activists from the Troubles.

Prior to this, the PSNI appeared only interested in those Boston College-Belfast Project tapes relating to the murder of Jean McConville by the IRA in 1972.

The PSNI has arrested seven people in relation to the kidnapping, killing and secret burial of the mother of 10. Among those it detained was Gerry Adams, the Sinn Féin president who a number of ex-IRA members claim gave the order for the widow to be secretly buried after being murdered for allegedly being an informer.

Adams has always denied any involvement in the McConville murder scandal or ever being in the IRA. At least one of the interviewees, the late Belfast IRA commander Brendan Hughes, alleged on tape that Adams gave the fateful order on the 37-year-old woman, whose remains were only found in 2003.

Ed Moloney, who founded the Belfast Project, called on the Obama administration to resist "this fishing expedition" by the PSNI.

Moloney said that to allow a raid on "an American college's private archive will be to undermine a peace deal that was in no small way the product of careful American diplomacy and peace building. The United States has the power to invoke vital foreign policy interests in order to reject this PSNI action."

Moloney, the author of a critically acclaimed history of the IRA, added: "I also called upon Boston College to vigorously resist this action and to rally the rest of American academe in the cause of research confidentiality."

Participants in the Belfast Project, both former IRA members and ex-loyalist paramilitaries, are currently involved in legal action to take back their tapes. Many of the loyalists want the material destroyed, fearing future arrests over past Troubles-related crimes. All of those who took part agreed to do so on the condition that the tapes would not be released until they were dead.

If the PSNI seized all of the Boston College archive material, it could lead to dozens of veteran IRA and loyalist paramilitaries being arrested.